Apoprotein(A) Isoforms and Plasma LP(A) Concentration in Members of Four Families
Apoprotein(a) is a multikringle protein which shows a genetically inherited size polymorphism. The APO(a) gene is located at the telomeric region of chromosome 6q2.6-q 2.7. Apo(a) size polymorphism is a major determinant of Lp(a) levels. The aim of this study is to describe the influence of apo(a) size polymorphism on the plasma Lp(a) levels in the members of four families. K3EDTA plasma was obtained from every subject after over-night fast. Apo(a) isoforms were determined by 3-15% SDS-PAGE followed by Western immunoblot technique. Plasma Lp(a) level was de - termined with immunonephelometric method. Every child inherited one isoform from its mother and the other from its father. The children from the first family had Lp(a) levels similar to those measured in their parents. The daughters from the second and fourth family inherited the dominant S3 apo(a) isoform from their mothers and also mother's high Lp(a) levels (0.365 g/L - daughter from the second, and 0.465 g/L and 0.446 g/L - daughter from the fourth family respectively). The elder daughter from the third family, carrier of double banded S4S1 apo(a) isoform, had the highest Lp(a) level among the children from all four families. We found out a generation decrease of the Lp(a) level in two families. On the basis of our findings we concluded that the inheritance of the apo(a) isoforms in the members of all four families is in accordance with the simple Mendelian's model and that the apo(a) size polymorphism influences the Lp(a) level in the blood of the examined subjects.